Pump inducers



NOV. 3 1964 F.| ATTANz1o ETAL 3,155,044

PUMP INnUcERs Filed Apm 12. 19Go FRA/v w RE/c ENBACHER sy ATTORNEY United States Patent O 3,155,044 PUMP INDUCERS Frank Lattanzio, West Hartford, and Frank W. Reichenbacher, East Hartford, Conn., assignors to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed Apr. 12, 1960, Ser. No. 21,835 6 Claims. (Cl. 103-88) This invention relates to a rotary inducer for a centrifugal pump.

One feature of the invention is a rotary inducer and reduction gear drive that can be readily mounted on or removed from the main pump. Another feature is a compact arrangement by which to obtain a rotary speed for the inducer which is substantially lower than the main pump speed with the inducer drive mechanism enclosed in the inducer casing.

One feature of the invention is an arrangement of the ducting from the inducer to the main pump such that the iiow through the inducer and into the main pump is symmetrical around the inducer and pump impeller axes with stationary vanes supporting the inner casing which encloses the bearings and reduction gear for the inducer.

Other features and advantages will be apparent from the specification and claims, and from the accompanying drawing which illustrates an embodiment of the invention.

The single ligure is a sectional view through a pump and associated inducer.

The housing 2 for the main pump impeller 4 has a mounting flange 6. The housing 2 carries a bearing 8 supporting the shaft 10 which serves to drive the impeller 4 and has a projecting end 12 on which the main pump inducer 14 is carried. The main inducer 14 has vanes 16 that are in alignment with the vanes on the main impeller 4. The projecting end 12 of the shaft 10 also carries a plurality of sealing fins 1S adjacent to the lefthand end thereof.

Fluid is admitted to the impeller through an annular duct 26 defined between an outer casing 28 and an inner casing 3l). The inner and outer casings are supported in concentric relation by stationary guide vanes or struts 32 integral with both casings. The outer casing has an attachment ange 34 at its right-hand end which is held as by bolts 36 to the ange 6 and a portion of the casing 28, accordingly, surrounds the vanes 16 and the main impeller 4.

The inner casing has a sealing ring 38 in a position to cooperate with the sealing fins 18, as shown, and this casing terminates in closely spaced relation to the impeller portion 14. The inner casing 30 has two axially spaced inwardly projecting flanges 40 and 42, the latter being adjacent to the end of the shaft projection 12 and supporting a bearing 44. This bearing supports a hollow shaft 46 carrying a plurality of axial splines 48 at its right-hand end in a position to engage with splines 50 internally positioned on the shaft 10. These splines are spaced remotely from the bearing 44 to reduce alignment problems in attaching the inducer to the main pump. Adjacent to the bearing 44 the shaft 46 carries a pinion 52 in a position to engage with an internal gear 54 on a Y hollow shaft 56 journalled in bearings 58 within the inner casing 30. The bearings 58 are supported by a ring 60 attached at its left-hand end to the flange 40 and supported at its right-hand end by the flange 42. The axis of the shaft 56 is offset from the axis of the shaft 46, as will le apparent, so that the pinion 52 and internal gear 54.1r'1ay be in engagement.

. 'At the opposite end of the shaft 56 is an integral pinion 62 meshing with an internal gear 64 on the end of a shaft 66. The latter is journalled in bearings 68 carried by a sleeve 70 forming a part of the inner casing and at- 3,155,044 Patented Nov. 3, 1964 kce tached as by bolts 71 to the inwardly projecting flange 40. The shaft 66 has mounted thereon the rotary inducer 72 having vanes 74 thereon located in the fluid llow path to the main pump. The inducer forms the inner wall of this fluid path and the outer wall is defined by a forward extension 28a of the outer casing 28.

The impeller may have mounted thereon a nose cone 76 to assist in directing the flow into the annular path. The casing 28a may be attached as by bolts 78 to the outer casing 28 so that the two parts in effect form the outer wall of the annular flow path from the inducer inlet to the main pump. A labyrinth seal 80 on the inner casing 40 cooperates with the downstream end of the inducer 72 to minimize fluid leakage.

In disassembly, the inducer and the reduction gear drive for the inducer may be removed from the main pump as a unitary assembly by the removal of the bolts 36. The unitary assembly may then be pulled to the left with the spline 48 pulling out of the splines 50. Thus, the inducer assembly may be removed or replaced as desired with a minimum effort and without affecting the assembly of the inducer, its casing and its reduction gear drive.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways Without departure from its spirit as defined by the following claims.

We claim:

1. The combination with a centrifugal pump having an impeller with a central spline and a surrounding casing, of an inducer assembly for delivering fluid under pressure to said pump, including an outer casing attached to the pump casing, an inner casing within said outer casing and spaced therefrom to define therebetween an annular passage for directing fluid to the impeller, a rotor mounted in said inner casing and having vanes extending into the annular passage, struts downstream of the rotor and extending between the inner and outer casings to support the inner casing, and driving means for the rotor positioned within said inner casing and including. a first shaft journalled in said inner casing and having a spline meshing with the central spline on the impeller, a gear carried by the rotor and reduction gear means supported by the inner casing between the shaft and the gear, said outer casing including a separable casing extension surrounding the rotor and removable from the remainder of the casing for access to the rotor, said reduction gear means including a first gear on said shaft, a second shaft journalled in said inner casing in offset parallel relation to said first shaft, said second shaft having an internal gear in mesh with the first gear, said second shaft also having an external gear thereon and said gear on the rotor meshing with said external gear.

2. A combination as in claim l in which the impeller spline is located in an axial bore in the impeller at a point remote from the gear in the first shaft and in which the impeller spline and rst shaft spline are axially slidable.

3. A combination as in claim 1 in which the first shaft is supported by a bearing adjacent to the gear thereon and remote from the spline.

4. An inducer, assembly including an outer casing, an inner casing within and spaced from said outer casing to form an annular passage for fluid between said casings, support means extending between the casings to support said casings in spaced relation, a rotor mounted in said inner casing and having vanes extending across the annular passage and driving means for said rotor including a first shaft journalled in said inner casing and having a spline thereon by which the shaft is driven and reduction gear means positioned Within said inner casing and connecting said shaft to the rotor, said reduction gear includ- 3 4 ing a first gear on said shaft, a second shaft journalled in the inducer assembly to an associated structure from said inner casing in eccentric relation to said shaft and which the shaft and therefore the rotor is driven. rotor, said second shaft having an internal gear in mesh With said first gear and also having an external gear References Cited in the file 0f this Patent thereon and said rotor having an internal gear in mesh 5 UNITED STATES PATENTS with the external gear on said second shaft. Y

5. An inducer assembly as in claim 4 in which the lsjlrsl; Nfgcug rst shaft is journalied Within the inner casing by a bearing adjacent to said first gear with the spline on said shaft FOREIGN PATENTS located at a point remote from the bearing. 10 579,780 Great Britain Aug. 15, 1946 6. An inducer assembly as in claim 5 in which the 677,835 Great Britain Aug. 20, 1952 outer casing carries attachment means for attachment of v697,235 Great Britain Sept. 16, 1963 

1. THE COMBINATION WITH A CENTRIFUGAL PUMP HAVING AN IMPELLER WITH A CENTRAL SPLINE AND A SURROUNDING CASING, OF AN INDUCER ASSEMBLY FOR DELIVERING FLUID UNDER PRESSURE TO SAID PUMP, INCLUDING AN OUTER CASING ATTACHED TO THE PUMP CASING, AN INNER CASING WITHIN SAID OUTER CASING AND SPACED THEREFROM TO DEFINED THEREBETWEEN AN ANNULAR PASSAGE FOR DIRECTING FLUID TO THE IMPELLER, A ROTOR MOUNTED IN SAID INNER CASING AND HAVING VANES EXTENDING INTO THE ANNULAR PASSAGE, STRUTS DOWNSTREAM OF THE ROTOR AND EXTENDING BETWEEN THE INNER AND OUTER CASINGS TO SUPPORT THE INNER CASING, AND DRIVING MEANS FOR THE ROTOR POSITIONED WITHIN SAID INNER CASING AND INCLUDING A FIRST SHAFT JOURNALLED IN SAID INNER CASING AND HAVING A SPLINE MESHING WITH THE CENTRAL SPLINE ON THE IMPELLER, A GEAR CARRIED BY THE ROTOR AND REDUCTION GEAR MEANS SUPPORTED BY THE INNER CASING BETWEEN THE SHAFT AND THE GEAR, SAID OUTER CASING INCLUDING A SEPARABLE CASING EXTENSION SURROUNDING THE ROTOR AND REMOVABLE FROM THE REMAINDER OF THE CASING FOR ACCESS TO THE ROTOR, SAID REDUCTION GEAR MEANS INCLUDING A FIRST GEAR ON SAID SHAFT, A SECOND SHAFT JOURNALLED IN SAID INNER CASING IN OFFSET PARALLEL RELATION TO SAID FIRST SHAFT, SAID SECOND SHAFT HAVING AN INTERNAL GEAR IN MESH WITH THE FIRST GEAR, SAID SECOND SHAFT ALSO HAVING AN EXTERNAL GEAR THEREON AND SAID GEAR ON THE ROTOR MESHING WITH SAID EXTERNAL GEAR. 